iagonal bracing visually strengthens deck posts Curved bracing repeating arched windows makes deck posts look less spindly Figure 1. Diagonal knee braces, though structurally unnecessary, give otherwise spindly-looking posts a more substantial look. These can be simple angled braces (top), or a repetition of a design element found elsewhere on the house (bottom). In the North Carolina mountains where I have my design practice, there's practically no such thing as a flat building lot. Many sites drop 20 feet or more along the side of the house, and it's not uncommon to find basements with sweeping views of distant mountains.